JP2591227B2 - Receiver for master station of time division multi-way multiplex communication system - Google Patents

Abstract

PURPOSE:To continue speech by each subscriber terminal even when a radio line hits by providing plural timer circuits, counting time instantaneously interrupting the radio line, and holding a loop monitor signal stored in a monitor signal memory circuit when the hit time is within time determined in advance. CONSTITUTION:When the radio line hits, a timer circuit 18 is activated and during the line hit time set in advance, a loop supervisory signal (e) to be outputted from a supervisory signal memory circuit 17 is held in a certain state before the generation of hit. Therefore, a transmission signal (c) of radio channels (i) and (j) under a line fault to a received signal processing circuit 15 holds the loop supervisory signal (e) in the state before the generation of hit as shown at the time of generating hit. Afterwards, when the radio line is recovered before the counted time of the timer circuit 18 to count the faulty time of the radio line exceeds the line hit time, the loop monitor signal is received from the subscriber terminal under the speech by using the radio channels (i) and (j). As a result, the normal speech is started again.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention extends a subscriber line of a local exchange to a multi-directional subscriber terminal using time division multiplexed radio signals on a plurality of radio channels. TECHNICAL FIELD The present invention relates to a time-division multi-way multiplex communication system for performing communication by means of a mobile station, and more particularly to a master station receiving apparatus.

[Conventional technology]

A conventional receiver for a master station in a time-division multi-way multiplex communication system will be described with reference to the drawings.

FIG. 2 is a block diagram of an embodiment of a conventional master station receiving apparatus.

The master station receiving device 3 of the time division multi-way multiplex communication system is connected to a plurality of slave stations 2a to 2c via an antenna 21 by radio lines. The slave station further includes a plurality of subscriber terminals, for example, slave stations.
2a is connected to the subscriber terminals 1a to 1c. The output terminal A of the master station receiver 3 is connected to a subscriber line (not shown) of the local exchange.

This time-division multi-directional multiplex communication system is a digital wireless communication system that uses one frequency, forms a plurality of time frames by time-division multiplexing one frequency, and performs communication using the time frame as a wireless channel. A plurality of fixed wireless channels are often allocated between the master station receiving device 3 and the slave stations, for example, to a wireless line between the slave stations 2a. Further, the number of subscriber terminals of a specific slave station is configured to be greater than the number of wireless channels assigned to the slave station. The signal of one wireless channel is constituted by a digital signal such as a communication signal and a control signal.

Now, a radio reception signal received from the slave station 2a via the antenna 21 is demodulated by the demodulator 22 into a baseband reception signal a and input to the reception signal fixing circuit 24. Radio signals transmitted by radio waves from the plurality of slave stations 2a to 2c are monitored by the radio line monitoring unit 23. If a radio link to a certain slave station, for example, the slave station 2a has failed, the radio link monitoring unit 23 sends the radio link fault information b indicating that the radio link to the slave station 2a is faulty. Send out. Then, the received signal fixing circuit 24 is controlled so that the closed / open state of the communication lines of the subscriber terminals 1a to 1c of the slave station 2a, that is, the loop state, is all determined to be the end by the wireless line failure information b. I was The reception signal fixing circuit 24 outputs a loop monitoring signal, which is one of the control signals in the reception signal a composed of a communication signal, a control signal, and the like by this control, when the subscriber terminals 1a to 1c end the call. The transmission signal c replaced with a predetermined signal is transmitted to the reception signal processing circuit 25. The reception signal processing circuit 25 is a circuit that performs call processing, communication signal processing, and the like of a wireless channel, and sends a reception signal as a processing result to the local exchange.

[Problems to be solved by the invention]

In the above-described conventional receiving apparatus for a time-division multi-way multiplex communication system, when a failure occurs in a radio line, a reception signal processing circuit loops all subscriber terminals connected to the failed slave station. Since the state is determined to be the end, all communication paths between the master station and each subscriber terminal connected to the failed slave station are disconnected. Therefore, even in the case of a failure that recovers after a momentary interruption of the wireless line, the communication path between the master station and the slave station is not restored, and each subscriber terminal must talk once and call again. There was a disadvantage that it did not.

[Means for Solving the Problems] The receiving device for a master station of the time-division multi-way multiplex communication system of the present invention includes one master station and a plurality of slave stations, and the master station is connected to a local exchange, The slave stations each accommodate a plurality of subscriber terminals, and perform time-division multi-directional multiplexing between the master station and each of the slave stations using a plurality of radio channels in which one frequency is time-division multiplexed. A monitoring signal separating circuit for separating a loop monitoring signal indicating a state of a loop of the plurality of subscriber terminals from a reception signal obtained by demodulating a wireless signal transmitted from each of the slave stations, A monitoring signal storage circuit that stores a loop monitoring signal of the plurality of subscriber terminals separated by the monitoring signal separation circuit for each of the plurality of wireless channels, and a monitoring unit that monitors the wireless signals and the slave station and the master station. By radio wave A radio line monitoring unit that transmits radio line fault information for each radio line when a radio line to be connected fails; counts the instantaneous interruption time of the radio line activated by the radio line fault information and determines the instantaneous interruption time in advance. A plurality of timer circuits corresponding to the plurality of wireless channels controlling the monitoring signal storage circuit so as to hold the loop monitoring signal stored in the monitoring signal storage circuit when the time is within a predetermined time; and A monitoring signal multiplexing circuit for replacing a loop monitoring signal of the received signal with a loop monitoring signal stored in the monitoring signal storage circuit.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of a master station receiving apparatus according to the present invention.

In FIG. 1, one of radio stations transmitted by radio waves from a plurality of slave stations (not shown) and received via an antenna 11
A radio signal forming a plurality of radio channels by frequency-division multiplexing a frequency is demodulated by a demodulator 12 into a baseband signal to become a received signal a. The monitoring signal separating circuit 16 converts a loop monitoring signal d representing a loop state of a plurality of subscriber terminals (not shown) accommodated in each of the slave stations from a reception signal a including a communication signal, a control signal, and the like. To separate. The monitoring signal storage circuit 17 stores the loop monitoring signal d separated by the monitoring signal separation circuit 16 at an address corresponding to a plurality of wireless channels with an identification number possessed for each subscriber terminal.

The timer circuit 18 detects the failure of the wireless line based on the wireless line failure information b sent by the wireless line monitoring unit 13 that monitors the plurality of wireless lines connected by wireless waves between the plurality of slave stations and the master station receiving device. Fired when it occurs. Timer circuit 18
Is configured to handle multiple wireless line failures,
The instantaneous line break time of the faulty wireless line is counted. If the “line instantaneous interruption time” of the wireless line counted by the timer circuit 18 exceeds a preset time, for example, a set time of about several hundred ms, the timer circuit 18 is stored in the monitoring signal storage circuit 17. The loop monitor signal is replaced with a signal indicating the end state.

The monitor signal multiplexing circuit 19 stores the loop monitor signal in the received signal a demodulated by the demodulator 12 into the monitor signal storage circuit 17.
The transmission signal c replaced with the loop monitoring signal e stored in the reception signal processing circuit 15 is transmitted. The received signal processing circuit 15 performs call processing, communication signal processing, and the like of the wireless channel, and sends the processed signal to a local exchange (not shown) via an output terminal A of the received signal.

Next, the operation of this embodiment will be described with reference to a time chart of the transmission signal c of the monitor signal multiplexing circuit 19 shown in FIG.

When the wireless line is normal, the monitor signal separating circuit 16 separates the loop monitor signal d from the received signal a received from the slave station, and stores the loop monitor signal d in the monitor signal storage circuit 17 for each wireless line. Further, the supervisory signal multiplexing circuit 19 replaces the loop supervisory signal of the received signal a received from the slave station with the loop supervisory signal e once stored in the supervisory signal storage circuit 17, and sends out the transmission signal c to the received signal processing circuit 15.

The transmission signal c at this time is shown in "normal state" in FIG. This figure shows that the subscriber terminal of a specific slave station
i and j are used, and the wireless channel k is unused. Also, r, s, and t are time slots of the loop monitoring signal e output from the monitoring signal storage circuit 17 and replaced with the loop monitoring signal of the received signal a.

Next, when the wireless line is momentarily interrupted, the timer circuit 18
Is activated, and the loop monitoring signal e output from the monitoring signal storage circuit 17 is maintained in a state before the instantaneous interruption during the preset “line instantaneous interruption time”. Therefore, the transmission signal c of the wireless channel i, j during the line failure to the reception signal processing circuit 15 holds the loop monitoring signal e in the state before the instantaneous interruption, as shown in "at the moment of interruption". At this time, the communication signal placed before the loop monitoring signal is not transmitted because the radio line is in failure.

Thereafter, a timer circuit 18 for counting the failure time of the wireless line
If the wireless line is restored before the counting time exceeds the “line instantaneous interruption time”, the loop monitoring signal is received from the subscriber terminal that was talking using the wireless channels i and j. The call resumes.

〔The invention's effect〕

As described above, according to the present invention, each subscriber terminal of the multi-directional multiplex communication system does not need to make a call once again even after a momentary interruption of the wireless line, and it is possible to continue the call without having to call again. Yes, its convenience is great.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing a conventional embodiment, and FIG. 3 is a diagram showing a time chart of a transmission signal of a master station receiving apparatus. 1a to 1c: subscriber terminal, 2a to 2c: slave station, 3: receiver for master station, 11, 21, antenna, 12, 22, demodulator, 13,2
3 …… Wireless line monitoring unit, 15,25 …… Received signal processing circuit, 16
…… Monitoring signal separation circuit, 17 …… Monitoring signal storage circuit, 18…
... Timer circuit, 19 ... Monitoring signal multiplexing circuit, 24 ... Received signal fixing circuit.

Claims (1)

(57) [Claims] 1. A master station and a plurality of slave stations, wherein said master station is connected to a local exchange, wherein said slave stations each accommodate a plurality of subscriber terminals, said master station and said respective child stations. In a master-station receiving device of a time-division multi-way multiplex communication system in which communication is performed using a plurality of radio channels obtained by time-division multiplexing one frequency with a station, a radio signal transmitted from each of the slave stations is transmitted. A monitoring signal separating circuit for separating a loop monitoring signal indicating a state of a loop of the plurality of subscriber terminals from the demodulated received signal, and a loop monitoring signal of the plurality of subscriber terminals separated by the monitoring signal separating circuit; A monitoring signal storage circuit for storing for each of a plurality of wireless channels, and transmitting wireless line fault information for each of the wireless lines when a wireless line for monitoring the wireless signals and connecting the slave station and the master station by wireless radio waves fails. Nothing A line monitoring unit that counts the instantaneous interruption time of the wireless line activated by the wireless line failure information and, when the instantaneous interruption time is within a predetermined time, the loop stored in the monitoring signal storage circuit; A plurality of timer circuits corresponding to the plurality of wireless channels controlling the monitoring signal storage circuit to hold a monitoring signal,
A supervisory signal multiplexing circuit for replacing a loop supervisory signal of the received signal with a loop supervisory signal stored in the supervisory signal storage circuit.